Broadband Mode (De)Multiplexer Formed With Phase-Matching of Multimode Access-Waveguide

A broadband mode (de)multiplexer [(De)MUX] is proposed and experimentally demonstrated based on a triple-waveguide coupler (TWC) with the phase-matching of a multimode access-waveguide. The tolerance to the operating wavelength and fabrication error of the proposed mode (De)MUX can be relaxed with the aid of the wider access-waveguide and the middle waveguide. The optimized mode (De)MUX is with a coupling length of 48 μ m and a broad bandwidth of >122 nm with the mode crosstalk of <; -15 dB. The optimized device was fabricated on a 220-nm-thick silicon-on-insulator platform and the measured results indicate that the operating bandwidth is 100 nm with the mode crosstalk lower than -14 dB.